She probably won't get nerfed as she hasn't been seeing a lot of play. Sadly, that does matter, and is why champions like Jayce weren't nerfed until after people started to permaban-pick him. That won't happen to Zyra anytime soon, because of all the mobility creep. She can manage her own, but won't be the best against all the gap-closing bruisers/mid laners.

But she isn't broken. She doesn't need any nerfs. She is a strong mid laner and that's about it. Riot balances according to the pro scene and popularity. If you look at all the recent changes it's on the champions that were perma-ban/pick status or highly picked over other champions. You basically only saw Skarner or Maokai jungle, and Skarner was nerfed. If a champion is secret-op they won't get nerfed until the champion explodes.